Many users have contact data stored in multiple different data sources. For example, a typical user may have contact data for work-related colleagues stored in a work email system, contact data for classmates stored in a school-provided computing system, and contact data for social acquaintances stored with several different social networking websites. The same person may have different contact data in several of the data sources. For example, a work telephone number for a user may be stored in contact data in the work email system, a school email address for the same user may be stored in contact data in the school-provided computing system, and a mobile telephone number for the same user may be stored in contact data in a social networking website. With contact data stored in the multiple different data sources, users have difficulty identifying which of the data areas stores particular contact data. For example, a user may have to search through several different data areas to find the email address of another user.
Some existing systems allow users to merge the contact information from the different data areas by copying the contact information into a new contact entry for each user and deleting duplicate information. With these existing systems, however, the users manually select and identify the contact data for merging. Further, because the contact data is copied into the new contact entry, the users have to manually update the new contact entry when changes are made to the original contact data in each of the data areas.